There has existed the need for a high speed punching assembly to be used with the higher speed turret punch presses. In prior punching assemblies, wear was excessive and too much time was required to remove and replace the punch in the punch assembly. The general objectives of the invention are to reduce wear, provide finished parts of better quality, i.e., flatter sheets, less burrs, longer punch life, quicker punch changing with more reliable and trouble free operation.
Punch devices have been previously proposed that include an external housing or sleeve within which the punch itself slides during operation. It is also known to provide a removable stripper plate surrounding the punch tip as shown for example in U.S. Pat. No. 4,248,111. These prior devices have certain shortcomings. When the punch is removed for sharpening, the bolt or other fastener holding it in place can fall out and be lost or misplaced. The punch clearance, i.e. extension adjustment of the punch, is also difficult to perform or is inaccurate.
In view of these and other deficiencies of the prior art, the present invention has the following more specific objectives and advantages:
a) The provision of an improved punching assembly having a means for more quickly and easily removing and replacing the punch; PA0 b) Provision for retaining the punch fastener, usually a bolt, in place within the assembly when the punch itself is removed; PA0 c) Provision for producing an audible signal when the punch has been released and is ready to be removed; and PA0 d) Provision for facilitating punch extension adjustment to compensate for punch length changes and the resulting amount of punch penetration into the die.
These and other more detailed specific objects of the invention will be apparent in view of the following description setting forth but a few of the various ways in which the present invention can be accomplished in view of the accompanying description which illustrates the invention by way of example.